[netinstall] Support selecting visible groups by default.

In other words, support:
  hidden: false
  selected: true
groups.

This was supposed to work according to README.md, but not actually
implemented. Now it should be working.

src/modules/netinstall/NetInstallPage.cpp

@@ -111,7 +111,7 @@ NetInstallPage::dataIsHere( QNetworkReply* reply )
             continue;
         }
 
-        GroupSelectionWidget* groupWidget = new GroupSelectionWidget( group.name, group.description, group.packages, this );
+        GroupSelectionWidget* groupWidget = new GroupSelectionWidget( group.name, group.description, group.packages, group.selected, this );
         m_groupWidgets.insert( groupKey, groupWidget );
         ui->groupswidget->layout()->addWidget( groupWidget );
 

src/modules/netinstall/widgets/groupselectionwidget.cpp

@@ -20,7 +20,7 @@
 
 #include <QtDebug>
 
-GroupSelectionWidget::GroupSelectionWidget( QString name, QString description, QStringList packages, QWidget* parent ) :
+GroupSelectionWidget::GroupSelectionWidget( QString name, QString description, QStringList packages, bool selected, QWidget* parent ) :
     QWidget( parent ),
     m_isToggled( false )
 {
@@ -29,6 +29,7 @@ GroupSelectionWidget::GroupSelectionWidget( QString name, QString description, Q
     connect( ui.group, &QCheckBox::toggled, this, &GroupSelectionWidget::toggleGroup );
 
     ui.group->setText( name );
+    ui.group->setChecked( selected ); // also triggers the toggleGroup slot
     ui.description->setText( description );
     const int columns = 4;
     const int rows = ( packages.size() - 1 ) / columns + 1;

src/modules/netinstall/widgets/groupselectionwidget.h

@@ -29,7 +29,7 @@ class GroupSelectionWidget : public QWidget
 {
     Q_OBJECT
 public:
-    explicit GroupSelectionWidget( QString name, QString description, QStringList packages, QWidget* parent = nullptr );
+    explicit GroupSelectionWidget( QString name, QString description, QStringList packages, bool selected, QWidget* parent = nullptr );
 
     // Current status of the group: is it selected in the view?
     bool isToggled() const;